checkDocs.js

#!/usr/bin/env node

// @flow

import fs from 'fs';
import path from 'path';
import {
  getRules,
  isFile,
} from './utilities';

const windows = (array, size) => {
  const output = [];

  for (let ii = 0; ii < array.length - size + 1; ii++) {
    output.push(array.slice(ii, ii + size));
  }

  return output;
};

const getDocIndexRules = () => {
  const content = fs.readFileSync(path.resolve(__dirname, '../../.README/README.md'), 'utf-8');

  const rules = content.split('\n').map((line) => {
    const match = /^{"gitdown": "include", "file": "([^"]+)"}$/.exec(line);

    if (match === null) {
      return null;
    } else {
      return match[1].replace('./rules/', '').replace('.md', '');
    }
  }).filter((rule) => {
    return rule !== null;
  });

  if (rules.length === 0) {
    throw new Error('Docs checker is broken - it could not extract rules from docs index file.');
  }

  return rules;
};

const hasCorrectAssertions = (docPath, name) => {
  const content = fs.readFileSync(docPath, 'utf-8');

  const match = /<!-- assertions ([a-zA-Z]+) -->/.exec(content);

  if (match === null) {
    return false;
  } else {
    return match[1] === name;
  }
};

/**
 * Performed checks:
 *  - file `/.README/rules/<rule>.md` exists
 *  - file `/.README/rules/<rule>.md` contains correct assertions placeholder (`<!-- assertions ... -->`)
 *  - rule is included in gitdown directive in `/.README/README.md`
 *  - rules in `/.README/README.md` are alphabetically sorted
 */
const checkDocs = (rulesNames) => {
  const docIndexRules = getDocIndexRules();

  const sorted = windows(docIndexRules, 2)
    .every((chunk) => {
      return chunk[0] < chunk[1];
    });

  if (!sorted) {
    throw new Error('Rules are not alphabetically sorted in `.README/README.md` file.');
  }

  const invalid = rulesNames.filter((names) => {
    const docPath = path.resolve(__dirname, '../../.README/rules', names[1] + '.md');
    const docExists = isFile(docPath);
    const inIndex = docIndexRules.includes(names[1]);
    const hasAssertions = docExists ? hasCorrectAssertions(docPath, names[0]) : false;

    return !(docExists && inIndex && hasAssertions);
  });

  if (invalid.length > 0) {
    const invalidList = invalid
      .map((names) => {
        return names[0];
      }).join(', ');

    throw new Error(
      'Docs checker encountered an error in: ' + invalidList + '. ' +
      'Make sure that for every rule you created documentation file with assertions placeholder in camelCase ' +
      'and included the file path in `.README/README.md` file.',
    );
  }
};

checkDocs(getRules());